In the Iranian Red Crescent Medical Journal issue published in June 2013, I read with great interest the article entitled “Frequency of all types of colorectal tumors in the patients referred to selected hospitals in Tehran”, by Golfam et al. (1). The authors briefly and incompletely reviewed the pathologic characteristics of the patients with colorectal cancer referring to two educational hospitals of Tehran University of Medical Sciences. They explored any association between the patients’ demographic characteristics (sex and age) and the tumor characteristics (location and differentiation). Nonetheless, some important pathologic data, including the type of surgery, surgical margin status, total number of identified lymph nodes, number of positive lymph nodes, presence of lymphatic-vascular and perineural invasion, presence of obstruction and/or perforation, and primary tumor stage, have been missed. These pathologic characteristics are important indicators for defining accurate tumor and lymph node staging and predicting the prognosis (2, 3). Furthermore, the findings of this study were influenced by an institutional referral bias. Higher male/female ratio (1.9:1) and higher proportion of rectal location (60%) are the examples of institutional referral biases in comparison to large national reports (4-7). Therefore, this is an incomplete pathology report-based study rather than an epidemiologic one.

Acknowledgements

The author expressed his gratitude to Ms. A. Keivanshekouh at the Research Improvement Center of Shiraz University of Medical Sciences for improving the use of English language in the manuscript.